Conventionally, a relatively considerable amount of studies have been made for upscaling technique with which resolution of inputted image data is enhanced.
The simplest methods of the resolution-enhancing technique can be, for example, a bilinear method, a bicubic method, and a LANCZOS method in which target pixel information is interpolated with the use of a simple filter. However, these methods only compensates, based on a specific rule, a gap between pixels in the inputted image data. Accordingly, the methods can only provide an image having sharpness substantially equivalent to that of an original image.
On the other hand, Patent Literature 1 for example discloses a technique in which an interpolation parameter is selected in accordance with a surrounding luminance pattern of a target pixel, and an upscaling process is carried out with the use of the selected interpolation parameter. Moreover, Patent Literature 1 also discloses a technique for improving, by experience and learning, accuracy of selecting a matching pattern in accordance with luminance variations.    Patent Literature 1    Japanese Patent No. 3243861 (Publication Date: Jun. 24, 1994)